There are neodymium magnets in the plugged holes, two in each side of the hexagon to keep the knives attached and aligned. The different heights of the sides allow for various blade lengths on the knives. The base is made from padauk, the hexagon cylinder is some mystery wood… maybe jatoba or bubinga. I finished it with waterlox original followed by a mineral oil / wax mixture for food safety.

Here are a couple progress pics:

Edit: I found out that the mystery wood is actually Jatoba. Nice-looking stuff.